This invention relates generally to forest thinning apparatus and, more particularly, to apparatus for bulk-lopping a plurality of felled trees and bucking and prestacking the same, all substantially simultaneously, and without the necessity for substantial human intervention.
In general, it can be said that no accepted mechanical solution has been devised for thinning a cultivated forest in a substantially mechanized or automated manner. Therefore, for the most part, the thinning of a forest generally necessitates and is accomplished utilizing a significant amount of heavy physical labor, such as that required during prestacking of the logs.
Of course, tree harvesting apparatus are known which generally include a traction device including a pair of juxtaposed feeding rolls between which the trunks of the felled trees are fed. Such apparatus is further provided with fixed lopping and bucking devices. Such conventional tree harvesters are not entirely satisfactory, however, in that the particular two-component trunk feeding mechanisms are capable of feeding only a single trunk at a time. In other words, a smaller diameter trunk which might be located adjacent to a larger one which is to be engaged by and fed between the pair of fixed feeding rolls, cannot be additionally accommodated between and gripped by the pair of feeding rollers. Thus, to the extent that it has been found necessary to be able to process several trees simultaneously to obtain maximum efficiency, these conventional tree harvesters have not been found satisfactory. Further, although tree harvesters are known in which four pulling or feeding rolls are permanently affixed to the machine frame, it is not possible with such structure to engage a felled tree or trees to lift the same into the lopping mechanism, even should such a harvester having four pulling rolls be attached to the free end of a movable boom.